1 //===- IdentifierTable.cpp - Hash table for identifier lookup -------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements the IdentifierInfo, IdentifierVisitor, and
10 // IdentifierTable interfaces.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/Basic/IdentifierTable.h"
15 #include "clang/Basic/CharInfo.h"
16 #include "clang/Basic/LangOptions.h"
17 #include "clang/Basic/OperatorKinds.h"
18 #include "clang/Basic/Specifiers.h"
19 #include "clang/Basic/TargetBuiltins.h"
20 #include "clang/Basic/TokenKinds.h"
21 #include "llvm/ADT/DenseMapInfo.h"
22 #include "llvm/ADT/FoldingSet.h"
23 #include "llvm/ADT/SmallString.h"
24 #include "llvm/ADT/StringMap.h"
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/ADT/Twine.h"
27 #include "llvm/Support/Allocator.h"
28 #include "llvm/Support/ErrorHandling.h"
29 #include "llvm/Support/raw_ostream.h"
30 #include <cassert>
31 #include <cstdio>
32 #include <cstring>
33 #include <string>
34 
35 using namespace clang;
36 
37 // A check to make sure the ObjCOrBuiltinID has sufficient room to store the
38 // largest possible target/aux-target combination. If we exceed this, we likely
39 // need to just change the ObjCOrBuiltinIDBits value in IdentifierTable.h.
40 static_assert(2 * LargestBuiltinID < (2 << (ObjCOrBuiltinIDBits - 1)),
41               "Insufficient ObjCOrBuiltinID Bits");
42 
43 //===----------------------------------------------------------------------===//
44 // IdentifierTable Implementation
45 //===----------------------------------------------------------------------===//
46 
47 IdentifierIterator::~IdentifierIterator() = default;
48 
49 IdentifierInfoLookup::~IdentifierInfoLookup() = default;
50 
51 namespace {
52 
53 /// A simple identifier lookup iterator that represents an
54 /// empty sequence of identifiers.
55 class EmptyLookupIterator : public IdentifierIterator
56 {
57 public:
58   StringRef Next() override { return StringRef(); }
59 };
60 
61 } // namespace
62 
63 IdentifierIterator *IdentifierInfoLookup::getIdentifiers() {
64   return new EmptyLookupIterator();
65 }
66 
67 IdentifierTable::IdentifierTable(IdentifierInfoLookup *ExternalLookup)
68     : HashTable(8192), // Start with space for 8K identifiers.
69       ExternalLookup(ExternalLookup) {}
70 
71 IdentifierTable::IdentifierTable(const LangOptions &LangOpts,
72                                  IdentifierInfoLookup *ExternalLookup)
73     : IdentifierTable(ExternalLookup) {
74   // Populate the identifier table with info about keywords for the current
75   // language.
76   AddKeywords(LangOpts);
77 }
78 
79 //===----------------------------------------------------------------------===//
80 // Language Keyword Implementation
81 //===----------------------------------------------------------------------===//
82 
83 // Constants for TokenKinds.def
84 namespace {
85 
86   enum {
87     KEYC99        = 0x1,
88     KEYCXX        = 0x2,
89     KEYCXX11      = 0x4,
90     KEYGNU        = 0x8,
91     KEYMS         = 0x10,
92     BOOLSUPPORT   = 0x20,
93     KEYALTIVEC    = 0x40,
94     KEYNOCXX      = 0x80,
95     KEYBORLAND    = 0x100,
96     KEYOPENCLC    = 0x200,
97     KEYC11        = 0x400,
98     KEYNOMS18     = 0x800,
99     KEYNOOPENCL   = 0x1000,
100     WCHARSUPPORT  = 0x2000,
101     HALFSUPPORT   = 0x4000,
102     CHAR8SUPPORT  = 0x8000,
103     KEYCONCEPTS   = 0x10000,
104     KEYOBJC       = 0x20000,
105     KEYZVECTOR    = 0x40000,
106     KEYCOROUTINES = 0x80000,
107     KEYMODULES    = 0x100000,
108     KEYCXX20      = 0x200000,
109     KEYOPENCLCXX  = 0x400000,
110     KEYMSCOMPAT   = 0x800000,
111     KEYALLCXX = KEYCXX | KEYCXX11 | KEYCXX20,
112     KEYALL = (0xffffff & ~KEYNOMS18 &
113               ~KEYNOOPENCL) // KEYNOMS18 and KEYNOOPENCL are used to exclude.
114   };
115 
116   /// How a keyword is treated in the selected standard.
117   enum KeywordStatus {
118     KS_Disabled,    // Disabled
119     KS_Extension,   // Is an extension
120     KS_Enabled,     // Enabled
121     KS_Future       // Is a keyword in future standard
122   };
123 
124 } // namespace
125 
126 /// Translates flags as specified in TokenKinds.def into keyword status
127 /// in the given language standard.
128 static KeywordStatus getKeywordStatus(const LangOptions &LangOpts,
129                                       unsigned Flags) {
130   if (Flags == KEYALL) return KS_Enabled;
131   if (LangOpts.CPlusPlus && (Flags & KEYCXX)) return KS_Enabled;
132   if (LangOpts.CPlusPlus11 && (Flags & KEYCXX11)) return KS_Enabled;
133   if (LangOpts.CPlusPlus20 && (Flags & KEYCXX20)) return KS_Enabled;
134   if (LangOpts.C99 && (Flags & KEYC99)) return KS_Enabled;
135   if (LangOpts.GNUKeywords && (Flags & KEYGNU)) return KS_Extension;
136   if (LangOpts.MicrosoftExt && (Flags & KEYMS)) return KS_Extension;
137   if (LangOpts.MSVCCompat && (Flags & KEYMSCOMPAT)) return KS_Enabled;
138   if (LangOpts.Borland && (Flags & KEYBORLAND)) return KS_Extension;
139   if (LangOpts.Bool && (Flags & BOOLSUPPORT)) return KS_Enabled;
140   if (LangOpts.Half && (Flags & HALFSUPPORT)) return KS_Enabled;
141   if (LangOpts.WChar && (Flags & WCHARSUPPORT)) return KS_Enabled;
142   if (LangOpts.Char8 && (Flags & CHAR8SUPPORT)) return KS_Enabled;
143   if (LangOpts.AltiVec && (Flags & KEYALTIVEC)) return KS_Enabled;
144   if (LangOpts.ZVector && (Flags & KEYZVECTOR)) return KS_Enabled;
145   if (LangOpts.OpenCL && !LangOpts.OpenCLCPlusPlus && (Flags & KEYOPENCLC))
146     return KS_Enabled;
147   if (LangOpts.OpenCLCPlusPlus && (Flags & KEYOPENCLCXX)) return KS_Enabled;
148   if (!LangOpts.CPlusPlus && (Flags & KEYNOCXX)) return KS_Enabled;
149   if (LangOpts.C11 && (Flags & KEYC11)) return KS_Enabled;
150   // We treat bridge casts as objective-C keywords so we can warn on them
151   // in non-arc mode.
152   if (LangOpts.ObjC && (Flags & KEYOBJC)) return KS_Enabled;
153   if (LangOpts.CPlusPlus20 && (Flags & KEYCONCEPTS)) return KS_Enabled;
154   if (LangOpts.Coroutines && (Flags & KEYCOROUTINES)) return KS_Enabled;
155   if (LangOpts.ModulesTS && (Flags & KEYMODULES)) return KS_Enabled;
156   if (LangOpts.CPlusPlus && (Flags & KEYALLCXX)) return KS_Future;
157   if (LangOpts.CPlusPlus && !LangOpts.CPlusPlus20 && (Flags & CHAR8SUPPORT))
158     return KS_Future;
159   return KS_Disabled;
160 }
161 
162 /// AddKeyword - This method is used to associate a token ID with specific
163 /// identifiers because they are language keywords.  This causes the lexer to
164 /// automatically map matching identifiers to specialized token codes.
165 static void AddKeyword(StringRef Keyword,
166                        tok::TokenKind TokenCode, unsigned Flags,
167                        const LangOptions &LangOpts, IdentifierTable &Table) {
168   KeywordStatus AddResult = getKeywordStatus(LangOpts, Flags);
169 
170   // Don't add this keyword under MSVCCompat.
171   if (LangOpts.MSVCCompat && (Flags & KEYNOMS18) &&
172       !LangOpts.isCompatibleWithMSVC(LangOptions::MSVC2015))
173     return;
174 
175   // Don't add this keyword under OpenCL.
176   if (LangOpts.OpenCL && (Flags & KEYNOOPENCL))
177     return;
178 
179   // Don't add this keyword if disabled in this language.
180   if (AddResult == KS_Disabled) return;
181 
182   IdentifierInfo &Info =
183       Table.get(Keyword, AddResult == KS_Future ? tok::identifier : TokenCode);
184   Info.setIsExtensionToken(AddResult == KS_Extension);
185   Info.setIsFutureCompatKeyword(AddResult == KS_Future);
186 }
187 
188 /// AddCXXOperatorKeyword - Register a C++ operator keyword alternative
189 /// representations.
190 static void AddCXXOperatorKeyword(StringRef Keyword,
191                                   tok::TokenKind TokenCode,
192                                   IdentifierTable &Table) {
193   IdentifierInfo &Info = Table.get(Keyword, TokenCode);
194   Info.setIsCPlusPlusOperatorKeyword();
195 }
196 
197 /// AddObjCKeyword - Register an Objective-C \@keyword like "class" "selector"
198 /// or "property".
199 static void AddObjCKeyword(StringRef Name,
200                            tok::ObjCKeywordKind ObjCID,
201                            IdentifierTable &Table) {
202   Table.get(Name).setObjCKeywordID(ObjCID);
203 }
204 
205 /// AddKeywords - Add all keywords to the symbol table.
206 ///
207 void IdentifierTable::AddKeywords(const LangOptions &LangOpts) {
208   // Add keywords and tokens for the current language.
209 #define KEYWORD(NAME, FLAGS) \
210   AddKeyword(StringRef(#NAME), tok::kw_ ## NAME,  \
211              FLAGS, LangOpts, *this);
212 #define ALIAS(NAME, TOK, FLAGS) \
213   AddKeyword(StringRef(NAME), tok::kw_ ## TOK,  \
214              FLAGS, LangOpts, *this);
215 #define CXX_KEYWORD_OPERATOR(NAME, ALIAS) \
216   if (LangOpts.CXXOperatorNames)          \
217     AddCXXOperatorKeyword(StringRef(#NAME), tok::ALIAS, *this);
218 #define OBJC_AT_KEYWORD(NAME)  \
219   if (LangOpts.ObjC)           \
220     AddObjCKeyword(StringRef(#NAME), tok::objc_##NAME, *this);
221 #define TESTING_KEYWORD(NAME, FLAGS)
222 #include "clang/Basic/TokenKinds.def"
223 
224   if (LangOpts.ParseUnknownAnytype)
225     AddKeyword("__unknown_anytype", tok::kw___unknown_anytype, KEYALL,
226                LangOpts, *this);
227 
228   if (LangOpts.DeclSpecKeyword)
229     AddKeyword("__declspec", tok::kw___declspec, KEYALL, LangOpts, *this);
230 
231   // Add the 'import' contextual keyword.
232   get("import").setModulesImport(true);
233 }
234 
235 /// Checks if the specified token kind represents a keyword in the
236 /// specified language.
237 /// \returns Status of the keyword in the language.
238 static KeywordStatus getTokenKwStatus(const LangOptions &LangOpts,
239                                       tok::TokenKind K) {
240   switch (K) {
241 #define KEYWORD(NAME, FLAGS) \
242   case tok::kw_##NAME: return getKeywordStatus(LangOpts, FLAGS);
243 #include "clang/Basic/TokenKinds.def"
244   default: return KS_Disabled;
245   }
246 }
247 
248 /// Returns true if the identifier represents a keyword in the
249 /// specified language.
250 bool IdentifierInfo::isKeyword(const LangOptions &LangOpts) const {
251   switch (getTokenKwStatus(LangOpts, getTokenID())) {
252   case KS_Enabled:
253   case KS_Extension:
254     return true;
255   default:
256     return false;
257   }
258 }
259 
260 /// Returns true if the identifier represents a C++ keyword in the
261 /// specified language.
262 bool IdentifierInfo::isCPlusPlusKeyword(const LangOptions &LangOpts) const {
263   if (!LangOpts.CPlusPlus || !isKeyword(LangOpts))
264     return false;
265   // This is a C++ keyword if this identifier is not a keyword when checked
266   // using LangOptions without C++ support.
267   LangOptions LangOptsNoCPP = LangOpts;
268   LangOptsNoCPP.CPlusPlus = false;
269   LangOptsNoCPP.CPlusPlus11 = false;
270   LangOptsNoCPP.CPlusPlus20 = false;
271   return !isKeyword(LangOptsNoCPP);
272 }
273 
274 tok::PPKeywordKind IdentifierInfo::getPPKeywordID() const {
275   // We use a perfect hash function here involving the length of the keyword,
276   // the first and third character.  For preprocessor ID's there are no
277   // collisions (if there were, the switch below would complain about duplicate
278   // case values).  Note that this depends on 'if' being null terminated.
279 
280 #define HASH(LEN, FIRST, THIRD) \
281   (LEN << 5) + (((FIRST-'a') + (THIRD-'a')) & 31)
282 #define CASE(LEN, FIRST, THIRD, NAME) \
283   case HASH(LEN, FIRST, THIRD): \
284     return memcmp(Name, #NAME, LEN) ? tok::pp_not_keyword : tok::pp_ ## NAME
285 
286   unsigned Len = getLength();
287   if (Len < 2) return tok::pp_not_keyword;
288   const char *Name = getNameStart();
289   switch (HASH(Len, Name[0], Name[2])) {
290   default: return tok::pp_not_keyword;
291   CASE( 2, 'i', '\0', if);
292   CASE( 4, 'e', 'i', elif);
293   CASE( 4, 'e', 's', else);
294   CASE( 4, 'l', 'n', line);
295   CASE( 4, 's', 'c', sccs);
296   CASE( 5, 'e', 'd', endif);
297   CASE( 5, 'e', 'r', error);
298   CASE( 5, 'i', 'e', ident);
299   CASE( 5, 'i', 'd', ifdef);
300   CASE( 5, 'u', 'd', undef);
301 
302   CASE( 6, 'a', 's', assert);
303   CASE( 6, 'd', 'f', define);
304   CASE( 6, 'i', 'n', ifndef);
305   CASE( 6, 'i', 'p', import);
306   CASE( 6, 'p', 'a', pragma);
307 
308   CASE( 7, 'd', 'f', defined);
309   CASE( 7, 'i', 'c', include);
310   CASE( 7, 'w', 'r', warning);
311 
312   CASE( 8, 'u', 'a', unassert);
313   CASE(12, 'i', 'c', include_next);
314 
315   CASE(14, '_', 'p', __public_macro);
316 
317   CASE(15, '_', 'p', __private_macro);
318 
319   CASE(16, '_', 'i', __include_macros);
320 #undef CASE
321 #undef HASH
322   }
323 }
324 
325 //===----------------------------------------------------------------------===//
326 // Stats Implementation
327 //===----------------------------------------------------------------------===//
328 
329 /// PrintStats - Print statistics about how well the identifier table is doing
330 /// at hashing identifiers.
331 void IdentifierTable::PrintStats() const {
332   unsigned NumBuckets = HashTable.getNumBuckets();
333   unsigned NumIdentifiers = HashTable.getNumItems();
334   unsigned NumEmptyBuckets = NumBuckets-NumIdentifiers;
335   unsigned AverageIdentifierSize = 0;
336   unsigned MaxIdentifierLength = 0;
337 
338   // TODO: Figure out maximum times an identifier had to probe for -stats.
339   for (llvm::StringMap<IdentifierInfo*, llvm::BumpPtrAllocator>::const_iterator
340        I = HashTable.begin(), E = HashTable.end(); I != E; ++I) {
341     unsigned IdLen = I->getKeyLength();
342     AverageIdentifierSize += IdLen;
343     if (MaxIdentifierLength < IdLen)
344       MaxIdentifierLength = IdLen;
345   }
346 
347   fprintf(stderr, "\n*** Identifier Table Stats:\n");
348   fprintf(stderr, "# Identifiers:   %d\n", NumIdentifiers);
349   fprintf(stderr, "# Empty Buckets: %d\n", NumEmptyBuckets);
350   fprintf(stderr, "Hash density (#identifiers per bucket): %f\n",
351           NumIdentifiers/(double)NumBuckets);
352   fprintf(stderr, "Ave identifier length: %f\n",
353           (AverageIdentifierSize/(double)NumIdentifiers));
354   fprintf(stderr, "Max identifier length: %d\n", MaxIdentifierLength);
355 
356   // Compute statistics about the memory allocated for identifiers.
357   HashTable.getAllocator().PrintStats();
358 }
359 
360 //===----------------------------------------------------------------------===//
361 // SelectorTable Implementation
362 //===----------------------------------------------------------------------===//
363 
364 unsigned llvm::DenseMapInfo<clang::Selector>::getHashValue(clang::Selector S) {
365   return DenseMapInfo<void*>::getHashValue(S.getAsOpaquePtr());
366 }
367 
368 namespace clang {
369 
370 /// One of these variable length records is kept for each
371 /// selector containing more than one keyword. We use a folding set
372 /// to unique aggregate names (keyword selectors in ObjC parlance). Access to
373 /// this class is provided strictly through Selector.
374 class alignas(IdentifierInfoAlignment) MultiKeywordSelector
375     : public detail::DeclarationNameExtra,
376       public llvm::FoldingSetNode {
377   MultiKeywordSelector(unsigned nKeys) : DeclarationNameExtra(nKeys) {}
378 
379 public:
380   // Constructor for keyword selectors.
381   MultiKeywordSelector(unsigned nKeys, IdentifierInfo **IIV)
382       : DeclarationNameExtra(nKeys) {
383     assert((nKeys > 1) && "not a multi-keyword selector");
384 
385     // Fill in the trailing keyword array.
386     IdentifierInfo **KeyInfo = reinterpret_cast<IdentifierInfo **>(this + 1);
387     for (unsigned i = 0; i != nKeys; ++i)
388       KeyInfo[i] = IIV[i];
389   }
390 
391   // getName - Derive the full selector name and return it.
392   std::string getName() const;
393 
394   using DeclarationNameExtra::getNumArgs;
395 
396   using keyword_iterator = IdentifierInfo *const *;
397 
398   keyword_iterator keyword_begin() const {
399     return reinterpret_cast<keyword_iterator>(this + 1);
400   }
401 
402   keyword_iterator keyword_end() const {
403     return keyword_begin() + getNumArgs();
404   }
405 
406   IdentifierInfo *getIdentifierInfoForSlot(unsigned i) const {
407     assert(i < getNumArgs() && "getIdentifierInfoForSlot(): illegal index");
408     return keyword_begin()[i];
409   }
410 
411   static void Profile(llvm::FoldingSetNodeID &ID, keyword_iterator ArgTys,
412                       unsigned NumArgs) {
413     ID.AddInteger(NumArgs);
414     for (unsigned i = 0; i != NumArgs; ++i)
415       ID.AddPointer(ArgTys[i]);
416   }
417 
418   void Profile(llvm::FoldingSetNodeID &ID) {
419     Profile(ID, keyword_begin(), getNumArgs());
420   }
421 };
422 
423 } // namespace clang.
424 
425 bool Selector::isKeywordSelector(ArrayRef<StringRef> Names) const {
426   assert(!Names.empty() && "must have >= 1 selector slots");
427   if (getNumArgs() != Names.size())
428     return false;
429   for (unsigned I = 0, E = Names.size(); I != E; ++I) {
430     if (getNameForSlot(I) != Names[I])
431       return false;
432   }
433   return true;
434 }
435 
436 bool Selector::isUnarySelector(StringRef Name) const {
437   return isUnarySelector() && getNameForSlot(0) == Name;
438 }
439 
440 unsigned Selector::getNumArgs() const {
441   unsigned IIF = getIdentifierInfoFlag();
442   if (IIF <= ZeroArg)
443     return 0;
444   if (IIF == OneArg)
445     return 1;
446   // We point to a MultiKeywordSelector.
447   MultiKeywordSelector *SI = getMultiKeywordSelector();
448   return SI->getNumArgs();
449 }
450 
451 IdentifierInfo *Selector::getIdentifierInfoForSlot(unsigned argIndex) const {
452   if (getIdentifierInfoFlag() < MultiArg) {
453     assert(argIndex == 0 && "illegal keyword index");
454     return getAsIdentifierInfo();
455   }
456 
457   // We point to a MultiKeywordSelector.
458   MultiKeywordSelector *SI = getMultiKeywordSelector();
459   return SI->getIdentifierInfoForSlot(argIndex);
460 }
461 
462 StringRef Selector::getNameForSlot(unsigned int argIndex) const {
463   IdentifierInfo *II = getIdentifierInfoForSlot(argIndex);
464   return II ? II->getName() : StringRef();
465 }
466 
467 std::string MultiKeywordSelector::getName() const {
468   SmallString<256> Str;
469   llvm::raw_svector_ostream OS(Str);
470   for (keyword_iterator I = keyword_begin(), E = keyword_end(); I != E; ++I) {
471     if (*I)
472       OS << (*I)->getName();
473     OS << ':';
474   }
475 
476   return std::string(OS.str());
477 }
478 
479 std::string Selector::getAsString() const {
480   if (InfoPtr == 0)
481     return "<null selector>";
482 
483   if (getIdentifierInfoFlag() < MultiArg) {
484     IdentifierInfo *II = getAsIdentifierInfo();
485 
486     if (getNumArgs() == 0) {
487       assert(II && "If the number of arguments is 0 then II is guaranteed to "
488                    "not be null.");
489       return std::string(II->getName());
490     }
491 
492     if (!II)
493       return ":";
494 
495     return II->getName().str() + ":";
496   }
497 
498   // We have a multiple keyword selector.
499   return getMultiKeywordSelector()->getName();
500 }
501 
502 void Selector::print(llvm::raw_ostream &OS) const {
503   OS << getAsString();
504 }
505 
506 LLVM_DUMP_METHOD void Selector::dump() const { print(llvm::errs()); }
507 
508 /// Interpreting the given string using the normal CamelCase
509 /// conventions, determine whether the given string starts with the
510 /// given "word", which is assumed to end in a lowercase letter.
511 static bool startsWithWord(StringRef name, StringRef word) {
512   if (name.size() < word.size()) return false;
513   return ((name.size() == word.size() || !isLowercase(name[word.size()])) &&
514           name.startswith(word));
515 }
516 
517 ObjCMethodFamily Selector::getMethodFamilyImpl(Selector sel) {
518   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
519   if (!first) return OMF_None;
520 
521   StringRef name = first->getName();
522   if (sel.isUnarySelector()) {
523     if (name == "autorelease") return OMF_autorelease;
524     if (name == "dealloc") return OMF_dealloc;
525     if (name == "finalize") return OMF_finalize;
526     if (name == "release") return OMF_release;
527     if (name == "retain") return OMF_retain;
528     if (name == "retainCount") return OMF_retainCount;
529     if (name == "self") return OMF_self;
530     if (name == "initialize") return OMF_initialize;
531   }
532 
533   if (name == "performSelector" || name == "performSelectorInBackground" ||
534       name == "performSelectorOnMainThread")
535     return OMF_performSelector;
536 
537   // The other method families may begin with a prefix of underscores.
538   while (!name.empty() && name.front() == '_')
539     name = name.substr(1);
540 
541   if (name.empty()) return OMF_None;
542   switch (name.front()) {
543   case 'a':
544     if (startsWithWord(name, "alloc")) return OMF_alloc;
545     break;
546   case 'c':
547     if (startsWithWord(name, "copy")) return OMF_copy;
548     break;
549   case 'i':
550     if (startsWithWord(name, "init")) return OMF_init;
551     break;
552   case 'm':
553     if (startsWithWord(name, "mutableCopy")) return OMF_mutableCopy;
554     break;
555   case 'n':
556     if (startsWithWord(name, "new")) return OMF_new;
557     break;
558   default:
559     break;
560   }
561 
562   return OMF_None;
563 }
564 
565 ObjCInstanceTypeFamily Selector::getInstTypeMethodFamily(Selector sel) {
566   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
567   if (!first) return OIT_None;
568 
569   StringRef name = first->getName();
570 
571   if (name.empty()) return OIT_None;
572   switch (name.front()) {
573     case 'a':
574       if (startsWithWord(name, "array")) return OIT_Array;
575       break;
576     case 'd':
577       if (startsWithWord(name, "default")) return OIT_ReturnsSelf;
578       if (startsWithWord(name, "dictionary")) return OIT_Dictionary;
579       break;
580     case 's':
581       if (startsWithWord(name, "shared")) return OIT_ReturnsSelf;
582       if (startsWithWord(name, "standard")) return OIT_Singleton;
583       break;
584     case 'i':
585       if (startsWithWord(name, "init")) return OIT_Init;
586       break;
587     default:
588       break;
589   }
590   return OIT_None;
591 }
592 
593 ObjCStringFormatFamily Selector::getStringFormatFamilyImpl(Selector sel) {
594   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
595   if (!first) return SFF_None;
596 
597   StringRef name = first->getName();
598 
599   switch (name.front()) {
600     case 'a':
601       if (name == "appendFormat") return SFF_NSString;
602       break;
603 
604     case 'i':
605       if (name == "initWithFormat") return SFF_NSString;
606       break;
607 
608     case 'l':
609       if (name == "localizedStringWithFormat") return SFF_NSString;
610       break;
611 
612     case 's':
613       if (name == "stringByAppendingFormat" ||
614           name == "stringWithFormat") return SFF_NSString;
615       break;
616   }
617   return SFF_None;
618 }
619 
620 namespace {
621 
622 struct SelectorTableImpl {
623   llvm::FoldingSet<MultiKeywordSelector> Table;
624   llvm::BumpPtrAllocator Allocator;
625 };
626 
627 } // namespace
628 
629 static SelectorTableImpl &getSelectorTableImpl(void *P) {
630   return *static_cast<SelectorTableImpl*>(P);
631 }
632 
633 SmallString<64>
634 SelectorTable::constructSetterName(StringRef Name) {
635   SmallString<64> SetterName("set");
636   SetterName += Name;
637   SetterName[3] = toUppercase(SetterName[3]);
638   return SetterName;
639 }
640 
641 Selector
642 SelectorTable::constructSetterSelector(IdentifierTable &Idents,
643                                        SelectorTable &SelTable,
644                                        const IdentifierInfo *Name) {
645   IdentifierInfo *SetterName =
646     &Idents.get(constructSetterName(Name->getName()));
647   return SelTable.getUnarySelector(SetterName);
648 }
649 
650 std::string SelectorTable::getPropertyNameFromSetterSelector(Selector Sel) {
651   StringRef Name = Sel.getNameForSlot(0);
652   assert(Name.startswith("set") && "invalid setter name");
653   return (Twine(toLowercase(Name[3])) + Name.drop_front(4)).str();
654 }
655 
656 size_t SelectorTable::getTotalMemory() const {
657   SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
658   return SelTabImpl.Allocator.getTotalMemory();
659 }
660 
661 Selector SelectorTable::getSelector(unsigned nKeys, IdentifierInfo **IIV) {
662   if (nKeys < 2)
663     return Selector(IIV[0], nKeys);
664 
665   SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
666 
667   // Unique selector, to guarantee there is one per name.
668   llvm::FoldingSetNodeID ID;
669   MultiKeywordSelector::Profile(ID, IIV, nKeys);
670 
671   void *InsertPos = nullptr;
672   if (MultiKeywordSelector *SI =
673         SelTabImpl.Table.FindNodeOrInsertPos(ID, InsertPos))
674     return Selector(SI);
675 
676   // MultiKeywordSelector objects are not allocated with new because they have a
677   // variable size array (for parameter types) at the end of them.
678   unsigned Size = sizeof(MultiKeywordSelector) + nKeys*sizeof(IdentifierInfo *);
679   MultiKeywordSelector *SI =
680       (MultiKeywordSelector *)SelTabImpl.Allocator.Allocate(
681           Size, alignof(MultiKeywordSelector));
682   new (SI) MultiKeywordSelector(nKeys, IIV);
683   SelTabImpl.Table.InsertNode(SI, InsertPos);
684   return Selector(SI);
685 }
686 
687 SelectorTable::SelectorTable() {
688   Impl = new SelectorTableImpl();
689 }
690 
691 SelectorTable::~SelectorTable() {
692   delete &getSelectorTableImpl(Impl);
693 }
694 
695 const char *clang::getOperatorSpelling(OverloadedOperatorKind Operator) {
696   switch (Operator) {
697   case OO_None:
698   case NUM_OVERLOADED_OPERATORS:
699     return nullptr;
700 
701 #define OVERLOADED_OPERATOR(Name,Spelling,Token,Unary,Binary,MemberOnly) \
702   case OO_##Name: return Spelling;
703 #include "clang/Basic/OperatorKinds.def"
704   }
705 
706   llvm_unreachable("Invalid OverloadedOperatorKind!");
707 }
708 
709 StringRef clang::getNullabilitySpelling(NullabilityKind kind,
710                                         bool isContextSensitive) {
711   switch (kind) {
712   case NullabilityKind::NonNull:
713     return isContextSensitive ? "nonnull" : "_Nonnull";
714 
715   case NullabilityKind::Nullable:
716     return isContextSensitive ? "nullable" : "_Nullable";
717 
718   case NullabilityKind::Unspecified:
719     return isContextSensitive ? "null_unspecified" : "_Null_unspecified";
720   }
721   llvm_unreachable("Unknown nullability kind.");
722 }
723